Direct Stripping Cyclone

ABSTRACT

Systems and methods for the separation of a particulate-fluid suspension are provided. An apparatus for the separation of a particulate-fluid suspension can include an enclosed vessel having two or more sections disposed coaxially along a common longitudinal centerline, wherein a first section has a first cross sectional area, and a second section has a second cross sectional area. A plurality of apertures can be disposed about the second section. The apparatus can have a cylindrical surface, parallel to the longitudinal centerline of the apparatus, disposed within the first section. A fluid distribution channel having a plurality of apertures can be disposed either about an exterior surface or an interior of the apparatus. A plurality of fluid conduits can provide fluid communication between the fluid distribution channel and the plurality of apertures distributed about the second section.

BACKGROUND

1. Field

The present embodiments generally relate to apparatus and methods forseparating particulate-fluid suspensions. More particularly, embodimentsof the present invention relate to apparatus and methods for separatingparticulate-fluid suspensions and stripping the settled particulateswithin a single vessel.

2. Description of the Related Art

Cyclonic separation has been used to separate a mixture or suspensioncontaining at least two components with differing densities, for examplesuspensions of particulates in a carrier fluid. The separation istypically accomplished by introducing the solid/fluid suspension to agenerally cylindrical separator on a tangential axis to the separator.The centrifugal force generated by the tangential introduction of thesuspension to the separator results in the accumulation of a dense solidphase along the walls of the separator, and, through centripetal motion,a less dense fluid phase in the center of the separator. In atraditional cyclonic separator, the solids can flow along the walls ofthe separator, accumulating at a low point in the separator for removal,while the relatively solids-free fluid can be withdrawn from the centerof the separator. Such cyclonic separation methods can be used to purifya solid or fluid phase, to concentrate a solid or fluid phase, toterminate chemical and physical interactions between mixed phases, orany combination thereof.

As with most separation processes, the cyclonic separation of asuspension into independent fluid and solid phases, can result in theentrapment and adsorption of fluid in the accumulated solids within theseparator. Accordingly, because of high reaction rates in catalyticcracking applications, an important consideration in cyclonic separationof light hydrocarbon products from the coke-covered particulate catalystis the displacement of the entrapped and/or adsorbed light hydrocarbonsfrom the separated particulate catalyst. Displacement of any entrappedor adsorbed light hydrocarbons from the separated particulate catalystwill minimize side-reactions between the catalyst and any residual lighthydrocarbons present in the settled particulate catalyst, therebyhelping to control conversion product profiles and to minimizeadditional “delta coking” on the surface of the particulate catalyst.

A need, therefore, exists for new apparatus and methods for separating asuspension containing a fluid and solid particulates, while strippingentrained fluid and adsorbed hydrocarbons from the separated solidsprior to removal from the separator.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the above recited features of the presentinvention can be understood in detail, a more particular description ofthe invention, briefly summarized above, may be had by reference toembodiments, some of which are illustrated in the appended drawings. Itis to be noted, however, that the appended drawings illustrate onlytypical embodiments of this invention and are therefore not to beconsidered limiting of its scope, for the invention may admit to otherequally effective embodiments.

FIG. 1 depicts an orthogonal sectional view of an illustrative separatoraccording to one or more embodiments described.

FIG. 2 depicts an orthogonal sectional view of another illustrativeseparator according to one or more embodiments described.

FIG. 3 depicts a partial cross-sectional view of an illustrativeseparator in operation in accordance with one or more embodimentsdescribed.

FIG. 4 depicts a partial cross-sectional view of an illustrativefluidized catalytic cracker incorporating one or more separatorsaccording to one or more embodiments described.

FIG. 5 shows the effect of fluid upward velocity on cyclone collectionefficiency, according to one or more embodiments described.

FIG. 6 shows the effect of stripping fluid upward velocity on vaporcontainment efficiency, according to one or more embodiments described.

DETAILED DESCRIPTION

A detailed description will now be provided. Each of the appended claimsdefines a separate invention, which for infringement purposes isrecognized as including equivalents to the various elements orlimitations specified in the claims. Depending on the context, allreferences below to the “invention” may in some cases refer to certainspecific embodiments only. In other cases it will be recognized thatreferences to the “invention” will refer to subject matter recited inone or more, but not necessarily all, of the claims. Each of theinventions will now be described in greater detail below, includingspecific embodiments, versions and examples, but the inventions are notlimited to these embodiments, versions or examples, which are includedto enable a person having ordinary skill in the art to make and use theinventions, when the information in this patent is combined withavailable information and technology.

Apparatus and methods for separating a particulate-fluid suspension areprovided. In one or more embodiments, an apparatus for the separation ofa particulate-fluid suspension can include an enclosed vessel having twoor more sections disposed coaxially along a common longitudinalcenterline, wherein a first section has a first cross sectional area,and a second section has a second cross sectional area. A plurality ofapertures can be disposed about the second section. The apparatus canhave a cylindrical surface, parallel to the longitudinal centerline ofthe apparatus, disposed within the first section. A distribution channelhaving a plurality of apertures can be disposed about an exteriorsurface of the apparatus. A plurality of fluid conduits can providefluid communication between the distribution channel and the pluralityof apertures distributed about the second section.

FIG. 1 depicts an orthogonal sectional view of an illustrative separator100 according to one or more embodiments. The separator 100 can be anenclosed vessel 110, having an integral separation (“first”) section120, stripping (“second”) section 130, and an inverted frustoconicalbottom 140 having one or more apertures 180 disposed therethrough. Inone or more embodiments, one or more nozzles can be disposed in each ofthe apertures 180. In one or more embodiments, a fluid distributionchannel 170 can be disposed about the separator 100. In one or moreembodiments, the fluid distribution channel 170 can be in fluidcommunication with the one or more apertures 180 and/or nozzles 185 viaone or more fluid conduits 190. In one or more embodiments, a strippingfluid can be introduced to the stripping section 130 of the separator100 via the fluid distribution channel 170, and nozzles 185. Theintroduction of the stripping fluid via one or more nozzles 185 canassist in removing entrained or entrapped gasses from the separatedsolids within the stripping section 130 of the separator 100.

In one or more embodiments, the separator 100 can include the first,separation, section 120 and the second, stripping, section 130. In oneor more embodiments, the diameter of the first and second sections 120,130 can be fixed to provide cylindrical members. In one or moreembodiments, the diameter of the first and second sections 120, 130 canbe variable to provide conical or frustoconical sections. In one or moreembodiments, any combination or frequency of fixed and variable sectionscan be used to provide the separator 100. In one or more embodiments,the inside diameter of the first section 120 can be identical to theinside diameter of the second section 130. In one or more embodiments,the first section 120 of the separator 100 can be an elongatedcylindrical member having a constant diameter (“d₁₂₀”) and crosssectional area (“A₁₂₀”), which defines an open, circular, cross sectionhaving a first (“upper”) end and a second (“lower”) end. In one or moreembodiments, the first section 120 can be fabricated from any heatresistant metal, including, but not limited to carbon steel, carbonsteel alloys, stainless steel, stainless steel alloys, nickel, nickelalloys, or any combination thereof.

In one or more embodiments, a laminate containing one or more abrasionresistant materials, including one or more high strength metals, such astungsten or commercially available abrasion resistant alloys including,but not limited to Manganol, Mangalloy, Hadfield, Tufloy, Formalloy,Chapalloy and/or Ultramet, can be bonded, attached, laminated ordisposed on all or a portion of the interior surface of the firstsection 120 of the separator 100. In one or more embodiments, one ormore non-metallic laminates, for example one or more laminatescontaining one or more abrasion resistant ceramic and/or refractorymaterials, can be disposed on all or a portion of the inner wall of thefirst section 120 of the separator 100. In one or more embodiments, thediameter, d₁₂₀, of the first section 120 can range from about 0.1 m (4in.) to about 10 m (32 ft.); from about 0.3 m (12 in.) to about 3 m (10ft.); or from about 0.5 m (1.6 ft.) to about 2 m (6.5 ft.).

The terms “up” and “down”; “upper” and “lower”; “upwardly” anddownwardly”; “upstream” and “downstream”; “above” and “below”; and otherlike terms as used herein refer to relative positions to one another andare not intended to denote a particular direction or spatialorientation.

One or more connections (“inlet connection”) 160 can be disposed on, inor about the wall forming the first section 120. In one or moreembodiments, the inlet connection 160 can enter the first section 120tangentially, i.e. with at least one side or edge of the fluid inletconnection at a tangent to the outside diameter of the first section120. In one or more embodiments, at least one side or edge of the inletconnection 160 can be aligned with the first, upper, end of the firstsection 120. The connection 160 can be four-sided, having a square orrectangular cross section with a dimension parallel to the longitudinalcenterline of the first section 120 ranging from about 0.1 d₁₂₀ to about0.75 d₁₂₀; about 0.2 d₁₂₀ to about 0.6 d₁₂₀; or about 0.25 d₁₂₀ to about0.5 d₁₂₀. The connection 160 dimension perpendicular to the longitudinalcenterline of the first section 120 can range from about 0.05 d₁₂₀ toabout 0.5 d₁₂₀; about 0.05 d₁₂₀ to about 0.15 d₁₂₀; or about 0.05 d₁₂₀to about 0.15 d₁₂₀. In one or more specific embodiments, the connection160 dimension parallel to the longitudinal centerline of the firstsection 120 can be 0.5 d₁₂₀. In one or more specific embodiments, theconnection 160 dimension perpendicular to the longitudinal centerline ofthe first section 120 can be 0.1 d₁₂₀.

The first, upper, end of the first section 120 can be partially orcompletely sealed using an end plate, cap or plug 105. In one or moreembodiments, a connection (“fluid outlet connection”) 155 can beconcentrically disposed through the end plate 105. The connection 155can provide a flowpath connecting the interior of the first section 120of the separator 100 with the exterior of the separator 100. Theconnection 155 can be any closed shape suitable for providing a conduitor channel fluidly connecting the interior and exterior of the separator100. In one or more embodiments, the connection 155 can be a pipe orduct having a constant diameter (“d₁₅₅”), i.e. circular, cross section.In one or more embodiments, all or a portion of the connection 155 canextend or internally project into the first section 120 of the separator100. In one or more embodiments, the connection 155 can project adistance into the first section 120 ranging from about 0.25 d₁₂₀ toabout 0.9 d₁₂₀; about 0.35 d₁₂₀ to about 0.75 d₁₂₀; or about 0.4 d₁₂₀ toabout 0.65 d₁₂₀. In one or more embodiments, the diameter, d₁₅₅, of thefluid discharge connection 155 can range from about 0.1 d₁₂₀ to about0.75 d₁₂₀; about 0.2 d₁₂₀ to about 0.6 d₁₂₀; or about 0.25 d₁₂₀ to about0.5 d₁₂₀. In one or more embodiments, the diameter, d₁₅₅, of theconnection can be 0.5 d₁₂₀.

The second section 130 can be formed as an elongated cylindrical memberhaving a constant inside diameter (“d₁₃₀”) and cross sectional area(“A₁₃₀”). The second section 130 of the separator 100 can define anopen, circular, cross section, having a first, upper, end and a second,lower, end. In one or more embodiments, the first section 120 and thesecond section 130 can be coaxially aligned along a common longitudinalcenterline of the separator 100. In one or more embodiments, the insidediameter, d₁₂₀, of the first section can equal the inside diameter,d₁₃₀, of the second section, as depicted in FIG. 1. Where the firstsection 120 and second section 130 share a common inside diameter, thefirst section 120 and the second section 130 can be directly attached orconnected. In one or more embodiments, the second section 130 can befabricated using one or more metallic and/or non-metallic, heatresistant, materials including, but not limited to, carbon steel, carbonsteel alloys, stainless steel, stainless steel alloys, nickel, nickelalloys, or any combination thereof. In one or more embodiments, theinside diameter, d₁₃₀, of the second section 130 can range from about0.1 m (4 in.) to about 10 m (32 ft.); from about 0.3 m (12 in.) to about3 m (10 ft.); or from about 0.5 m (1.6 ft.) to about 2 m (6.5 ft.).

The one or more stabilizers 135 can be disposed within the separator100. In one or more embodiments, the one or more stabilizers can beinternally disposed in coaxial alignment with the longitudinalcenterline of the separator 100. In one or more specific embodiments,the stabilizer 135 can be disposed internally within the separator 100,at the intersection of the first and second sections 120, 130. In one ormore embodiments, the stabilizer 135 can be a hollow, right, conicsection having an opening angle ranging from about 20° to about 180°;about 45° to about 135°; or about 45° to about 90°. In one or morespecific embodiments, the stabilizer 135 can be a hollow, right, conicsection having an opening angle of about 90°. In one or moreembodiments, the stabilizer 135 can be disposed with the apex of theconical stabilizer disposed towards the first section 120. In one ormore embodiments, the stabilizer 135 can be disposed with the base ofthe stabilizer 135 forming an angle of from about 60° to about 90°measured with respect to the longitudinal centerline of the separator100. In one or more embodiments, the base of the stabilizer 135 can forman angle of about 90° measured with respect to the longitudinalcenterline of the separator 100. In one or more embodiments, thetransverse disposition of the stabilizer 135 within the separator 100can form a continuous or segmented annular passage between the outsideperimeter of the base of the stabilizer 135 and the interior surfaceand/or wall of the separator 100. In one or more embodiments, thestabilizer 135 can have a centering rod externally attached to the apexof the cone, projecting from the stabilizer 135 for a distance ofbetween 0.25 and 10 times the overall height of the cone forming thestabilizer 135. The base diameter of the stabilizer 135 can range fromabout 0.25 d₁₃₀ to about 0.8 d₁₃₀; from about 0.3 d₁₃₀ to about 0.75d₁₃₀; or from about 0.5 d₁₃₀ to about 0.75 d₁₃₀.

A transition section 140 can be disposed coaxially along thelongitudinal centerline of the separator 100 between the second section130 and one or more connections (“particulate discharge connections”)150. In one or more embodiments, the transition section 140 can have afrustoconical configuration with a first, upper, end having a diameterequal to the diameter of the second section 130 d₁₃₀ and a second,lower, end having a diameter equal to the diameter of the connection150, d₁₅₀. In one or more embodiments, the upper end of the transitionsection 140 can connect to the second, lower, end of the second section130 while the lower end of the transition section 140 can attach to theone or more connections 150. In one or more embodiments, the length ofthe transition section 140, as measured along the longitudinal axis ofthe separator 100, can range from about 0.75 d₁₂₀ to about 0.5 d₁₂₀;about 0.1 d₁₂₀ to about 0.4 d₁₂₀; or about 0.1 d₁₂₀ to about 3 d₁₂₀.

One or more apertures 180 can be disposed in any number, order,arrangement, frequency, or configuration about the wall forming thetransition section 140. In one or more embodiments, one or more couplingdevices, such as one or more weld-o-lets, thread-o-lets, or anycombination thereof, can be disposed on the exterior surface of thetransition section 140, about each aperture 180. In one or moreembodiments, the apertures 180 can be of uniform diameter. In one ormore embodiments, the apertures 180 can have two or more differentdiameters. In one or more embodiments, one or more nozzles 185 can beinstalled within the one or more apertures 180. In one or moreembodiments, the diameter of the apertures 180 can range from about 0.6cm (0.25 in.) to about 7.5 cm (3 in.); from about 1.3 cm (0.5 in.) toabout 5 cm (2 in.); or from about 1.3 cm (0.5 in) to about 3.7 cm (1.5in.).

In one or more embodiments, the one or more connections 150 can beattached to the lower end the transition section 140. In one or moreembodiments, the one or more connections 150 can be coaxially alignedwith the longitudinal centerline of the separator 100. In one or moreembodiments, settled solids can be removed from the second section 130of the separator 100 via the one or more connections 150. The connection150 can be any closed shape capable of providing a fluid conduit orchannel connecting the interior and the exterior of the separator 100.In one or more embodiments, the connection 150 can be a pipe or duct ofcircular cross section, having a diameter d₁₅₀. In one or moreembodiments, the diameter of the connection 150 can range from about 0.1d₁₂₀ to about 0.75 d₁₂₀; about 0.2 d₁₂₀ to about 0.6 d₁₂₀; or about 0.25d₁₂₀ to about 0.5 d₁₂₀. In one or more specific embodiments, thediameter of the connection 150 can be 0.4 d₁₂₀.

In one or more embodiments, a distribution header (“fluid distributionchannel”) 170 can be disposed externally about the second section 130 ofthe separator 100. The fluid distribution channel 170 can have anyclosed shape capable of providing a continuous fluid conduit connectingthe one or more fluid inlets 175 to the one or more fluid conduits 190disposed about the separator 100. In one or more embodiments, thedistribution channel 170 can be a plenum attached directly to theexterior wall of the separator 100, for example a three-sided, U-shaped,plenum using the exterior surface of the separator wall 100 as a fourthside of the distribution channel 170. In one or more embodiments, thedistribution channel 170 can be made of any available pipe or tubing ofa diameter selected to minimize the pressure drop within thedistribution channel 170. In one or more embodiments, one or more inlets175, connecting the distribution channel 170 to one or more externalfluid supplies, can be disposed in any order or configuration about thedistribution header 170. In one or more embodiments, the diameter of thedistribution channel 170 can range from about 2.5 cm (1 in.) to about 15cm (6 in.); from about 3.7 cm (1.5 in.) to about 10 cm (4 in.); or fromabout 3.7 cm (1.5 in.) to about 7.5 cm (3 in.).

In one or more embodiments, one or more fluid conduits 190 can connectthe distribution channel 170 to the one or more nozzles 185. In one ormore embodiments, the diameter of the one or more fluid conduits 190 canbe selected to minimize the overall pressure drop between the externalfluid supply and the nozzles 185. In one or more embodiments, the one ormore fluid conduits 190 can be connected to the distribution header 170via threads, flanges, quick connect connectors such as cam-lockfittings, and/or welding. In one or more embodiments, the one or morefluid conduits 190 can be connected to the one or more nozzles 185 viathreads, flanges, quick connect connectors, and/or welding. In one ormore embodiments, one or more quarter-turn isolation valves (not shown)can be disposed in some or all of the fluid conduits 190. In one or moreembodiments, one or more needle or similar type throttling valves (notshown) can be disposed in some or all of the fluid conduits 190. In oneor more embodiments, the one or more fluid conduits 190 can befabricated using metallic and/or non-metallic rigid piping, rigidtubing, flexible tubing, flexible piping wire reinforced flexible pipingor any combination thereof. In one or more embodiments, the diameter ofthe fluid conduits 190 can range from about 0.6 cm (0.25 in.) to about 5cm (2 in.); from about 1.3 cm (0.5 in.) to about 3.8 cm (1.5 in.); orfrom about 1.3 cm (0.5 in.) to about 2.5 cm (1 in.).

One or more nozzles 185 can be disposed in each aperture 180 located inthe transition section 140. The one or more nozzles can provide an evendistribution of fluid supplied by the fluid channel 170 to the nozzles185 via the one or more fluid conduits 190 within the second section130. In one or more embodiments, the nozzles 185 disposed in thetransition section can be identical. In one or more embodiments, thenozzles 185 disposed in the transition section can include two or moredifferent types of distribution nozzles. In one or more embodiments, thenozzles 185 can include one or more non-clogging type which can preventthe entry of solids from the transition section into the nozzles 185.Typical fluid distribution nozzles 185 can include, but are not limitedto Bete NF fan nozzles, Bete FF fan nozzles, and/or Bete MP whirl typenozzles.

FIG. 2 depicts an orthogonal sectional view of another illustrativeseparator 200 according to one or more embodiments. The separator 200depicted in FIG. 2 can be an enclosed vessel 110, with integralseparation (“first”) section 120 having a first diameter d₁₂₀, stripping(“second”) section 130 having a second diameter d₁₃₀, and an invertedfrustoconical bottom 140 having one or more apertures 180 disposedtherethrough. In one or more embodiments, one or more nozzles 185 can bedisposed in each of the apertures 180. In one or more embodiments, afluid distribution channel 170 can be disposed about an exteriorcircumference of the second section 130 of the separator 100. In one ormore embodiments, the fluid distribution channel 170 can be in fluidcommunication with the one or more apertures 180 and/or nozzles 185 viaone or more fluid conduits 190.

The first and second sections 120, 130 of the separator 200, as depictedin FIG. 2, can have a two or more inside diameters. In one or morespecific embodiments, the inside diameter d₁₂₀ of the first section 120can be greater than the inside diameter of the second section 130, d₁₃₀.The upper end of the second section 130 can be attached to the lower endof the first section 120 by one or more transition sections 125. In oneor more embodiments, the transition section 125 can be a frustoconicalmember disposed between the lower end of the first section 120 and theupper end of the second section 130. In one or more specificembodiments, the transition section 125 can be an annular member, havingan outside diameter equal to the diameter d₁₂₀ of the second, lower, endof the first section 120 and an inside diameter equal to the diameterd₁₃₀ of the first, upper, end of the second section 130.

FIG. 3 depicts a partial cross-sectional view of an illustrativeseparator in operation in accordance with one or more embodiments. Inoperation, a particulate-fluid suspension 310 can be introduced to theseparator 100 via the connection 160. A relatively particulate-freefluid phase 330 can be withdrawn via the connection 155, while arelatively fluid-free particulate phase 370 can be withdrawn via theconnection 150.

Within the first section 120, centrifugal force imparted by thetangential entry of the particulate-fluid suspension 310, can propel thehigher density particulates contained in the particulate-fluidsuspension 310 towards the outside wall of the separator 100. Theparticulates, having a greater density than the fluid in line 310, cansettle into the second section 130 of the separator, forming aparticulate bed 350 therein. The lower density fluid phase can flow viacentripetal motion towards the center of the first section 120 of thedirect stripping separator 100 for removal via the connection 155. Inone or more embodiments, the solids concentration in the fluid phase 330removed from the separator 100 via the connection 155 can be less thanabout 25% wt. solids; less than about 20% wt. solids; less than about15% wt. solids; less than about 10% wt. solids; less than about 5% wt.solids; or less than about 1% wt. solids.

In one or more embodiments, one or more fluids 360 can be introducedfrom an external supply (not shown) to the distribution channel 170 viathe one or more inlets 175. The fluid 360 can be introduced via the oneor more fluid conduits 190 and nozzles 185 at one or more points in thetransition section 140. The selection of an appropriate fluid 360 candepend on a variety of factors, including the composition of theparticulates, as well as compatibility with process fluids and products.For example, in catalytic cracking service, steam can be used to provideat least a portion of the stripping fluid 360. In one or moreembodiments, the stripping fluid can flow upward through the settledparticulates (“particulate bed”) 350, stripping any residual processfluids trapped within the settled particulates into the first section120 for removal via fluid discharge connection 155. In one or moreembodiments, the introduction of the one or more fluids 360 to thesettled particulates 350 can fluidize the settled particulates 350,thereby forming a highly turbulent, “rolling” suspension of particulatessuspended in the fluid. In one or more embodiments, the particulateconcentration in the particulate discharge 370 from the second section130 can be about 40% wt. or more; about 60% wt. or more; about 80% wt.or more; about 90% wt. or more; about 95% wt. or more; or about 99% wt.or more.

FIG. 4 depicts a partial cross-sectional view of an illustrativefluidized catalytic cracker (“FCC”) 400 incorporating one or moreseparators 100 according to one or more embodiments. Although notdepicted in FIG. 4, in one or more embodiments, a hydrocarbon feed,steam and particulate catalyst can be introduced to a riser reactor(“riser”) 410. Within the riser 410, the hydrocarbon feed can crack,forming one or more gaseous light hydrocarbon products and one or moreheavy hydrocarbon by-products which can deposit as a layer ofcarbonaceous coke on the surface of the particulate catalyst.

The gaseous light hydrocarbons and coke-covered particulate catalyst canexit the riser 410 as a particulate-fluid suspension via duct 415. Inone or more embodiments, the particulate-fluid suspension in duct 415can be introduced via the connection 160 to the first section 120 of theone or more separators 100 located within the separator 420. Within thefirst section 120, the coke-covered particulate catalyst can beselectively separated from the one or more gaseous light hydrocarbonproducts. In one or more embodiments, the one or more gaseous lighthydrocarbon products can be withdrawn from the separator 100 via adischarge duct 460. In one or more embodiments, as depicted in FIG. 4,the separator 100 can be slip-fitted to the discharge duct 460 withinthe separator 420. Slip fitting of the separator 100 to the dischargeduct 460 can eliminate the need for an expansion joint between theseparator 100 and the discharge duct 460.

The coke covered particulate catalyst from the first section 120 cansettle into the second section 130 and the transition section 140 of theseparator 100. One or more stripping fluids, for example steam, can beintroduced to the separator 100 via one or more nozzles 185 located inone or more apertures 180 disposed in a wall of the transition section140 of the separator 100. The stripping fluid introduced via the one ormore nozzles 185 can mix with the coke covered particulate catalystaccumulated in the second section 130 and transition section 140,forming a turbulent, fluidized bed therein.

The turbulent mixing of the settled coke-covered particulate catalystwith one or more stripping fluids in the in the second section 130 ofthe separator 100 can strip, separate or otherwise remove any residuallight hydrocarbon products from the coke-covered particulate catalyst.The coke-covered particulate catalyst can be removed from the separator100 via the connection 150. In one or more embodiments, the separator100 can be operated at a positive pressure, i.e. a pressure greater thanthe ambient pressure within the separator 420 surrounding the separator100.

In one or more embodiments, after passing through the discharge 155, thecoke-covered particulate catalyst can drop through duct 430 to adischarge valve 440. In one or more embodiments, the discharge valve 440can be modulated, i.e. cycled open and closed, to control theaccumulation of coke-covered particulate catalyst within the separator100. The coke covered particulate catalyst passing through the valve 440can fall into a regenerator section 450 of the separator vessel 420.Within the regenerator section 450, the coke covering the particulatecatalyst can be combusted or otherwise removed from the particulatecatalyst, thereby forming a waste gas containing carbon monoxide andcarbon dioxide and clean, regenerated catalyst. The regenerated catalystcan be removed from the separator vessel 420 via one or more dischargeconnections 485. The waste gas can be exhausted from the separatorvessel 420 for further treatment and/or recovery (not shown). All or aportion of the regenerated particulate catalyst removed via the one ormore discharge connections 485 can be recycled for use within the riser410.

In one or more embodiments, the one or more gaseous light hydrocarbonsremoved from the separator 100 via the discharge duct 460. The separator100 can be fitted to the discharge duct 460 without the use of anexpansion joint. The lack of an expansion joint between the separator100 and the duct 460 can eliminate the need for one or more overpressureprotection devices on the separator 100 since the separator 100 and theduct 460 are not sealed. The gaseous light hydrocarbons removed via thedischarge duct 460 can be introduced to one or more second stagecyclones 470. Within the one or more second stage cyclones 470 anyresidual particulate catalyst present can be selectively separated fromthe one or more gaseous light hydrocarbon products. Any particulatecatalyst removed in the second stage cyclones 470 can fall through thesecond stage cyclone 470 into a discharge duct 490 and thence into theregeneration section 450 within the separator 420. In one or moreembodiments, the one or more gaseous light hydrocarbon products can bewithdrawn from the second stage cyclones 470 and exit the separator 420via discharge duct 490.

EXAMPLES

The foregoing discussion can be further described with reference to thefollowing non-limiting examples.

Example 1 illustrates the effect of stripping fluid upward velocity oncatalyst collection efficiency (percentage of solids entering theseparator 100 via inlet 160 and exiting via connection 150) usingcomparable direct stripping and self stripping separators. The feedvelocity was maintained constant at 10.7 m/sec (35 ft/sec) and the feedparticulate loading was maintained constant at about 16 kg/m³ (1.2lb/ft³) for the duration of the test. In each case, the upward velocityof the stripping fluid was varied between 0.2 m/sec (0.5 ft/sec) and 1.1m/sec (3.5 ft/sec) and the catalyst collection efficiency was measured.FIG. 5 shows the effect of the fluid upward velocity in relation to thecyclone collection efficiency.

As demonstrated by the data presented in FIG. 5, at relatively lowupward velocities of from about 0.2 m/sec (0.5 ft/sec) to about 0.7m/sec (2.2 ft/sec) the catalyst collection efficiency of the directstripping and self-stripping separators was comparable. At greaterupward velocities, i.e. about 0.9 m/sec (3.0 ft/sec) or more, thecollection efficiency of the direct stripping cyclone 100 provided asignificant (5% to 7%) performance improvement over a self-strippingcyclone operating with a comparable inlet velocity and solids loading.

Example 2 illustrates the effect of stripping fluid upward velocity onvapor containment efficiency (percentage of gas that enters theseparator via inlet 160 and exits via line 155) of a direct-strippingcyclone 100. In the direct-stripping cyclone 100, the stripping fluidwas introduced into the stripping section 130 via one or more nozzles185.

The feed velocity to the direct-stripping cyclone was maintained at 10.7m/sec (35 ft/sec) while the feed particulate loading was varied fromabout 10.4 kg/m³ (0.65 lb/ft³) to about 24.0 kg/m³ (1.5 lb/ft³). Theupward velocity of the stripping fluid was varied from about 0.06 m/sec(0.2 ft/sec) to about 0.8 m/sec (2.7 ft/sec). FIG. 6 shows the effect ofstripping fluid upward velocity in relation to vapor containmentefficiency.

As shown in FIG. 6, the vapor collection efficiency was significantlyimproved, i.e. about 30%, by increasing the upward velocity of thestripping fluid within the direct-stripping cyclone 100, which separateda substantial portion of the gas from the feed. Also, the quantity ofgas entrained in the settled solids collected in the stripping section130 was surprisingly reduced by increasing the gas separation in theseparation section 120 of the direct-stripping cyclone 100. Further, theincreased upward velocity of the stripping fluid within thedirect-stripping cyclone 100 did not substantially affect the solidscollection efficiency of the direct-stripping cyclone 100.

Certain embodiments and features have been described using a set ofnumerical upper limits and a set of numerical lower limits. It should beappreciated that ranges from any lower limit to any upper limit arecontemplated unless otherwise indicated. Certain lower limits, upperlimits and ranges appear in one or more claims below. All numericalvalues are “about” or “approximately” the indicated value, and take intoaccount experimental error and variations that would be expected by aperson having ordinary skill in the art.

Various terms have been defined above. To the extent a term used in aclaim is not defined above, it should be given the broadest definitionpersons in the pertinent art have given that term as reflected in atleast one printed publication or issued patent. Furthermore, allpatents, test procedures, and other documents cited in this applicationare fully incorporated by reference to the extent such disclosure is notinconsistent with this application and for all jurisdictions in whichsuch incorporation is permitted.

While the foregoing is directed to embodiments of the present invention,other and further embodiments of the invention may be devised withoutdeparting from the basic scope thereof, and the scope thereof isdetermined by the claims that follow.

1) A apparatus for separating particulate-fluid suspensions comprising:a cylindrical first section having a first inside diameter; acylindrical second section having a second inside diameter, wherein thefirst and second sections are disposed coaxially along a commonlongitudinal centerline; a right conical stabilizer disposed coaxiallyalong the common longitudinal centerline between the first and secondsections, wherein the stabilizer is disposed with the apex towards thefirst section, and wherein the stabilizer has a base diameter less thanthe second inside diameter; an annular fluid distribution channel havinga plurality of apertures formed therethrough, wherein the fluiddistribution channel is disposed about an outer diameter of the secondsection; a plurality of apertures disposed about a lower portion of thesecond section; and a plurality of fluid conduits, each fluid conduitconnecting one or more apertures on the fluid distribution channel toone or more apertures on the lower portion of the second section. 2) Theapparatus of claim 1, wherein the first inside diameter is equal to thesecond inside diameter. 3) The apparatus of claim 1, wherein the firstinside diameter is greater than the second inside diameter. 4) Theapparatus of claim 1, wherein one or more fluid distribution nozzles aredisposed in each of the apertures disposed about the second section. 5)The apparatus of claim 1, wherein the external fluid distributionchannel comprises an annular, ring-shaped, fluid conduit disposed aboutthe second section. 6) The apparatus of claim 1, wherein the pluralityof apertures are distributed symmetrically about the second section. 7)The apparatus of claim 1, wherein the plurality of apertures aredistributed asymmetrically about the second section. 8) The apparatus ofclaim 1 further comprising a tangential connection disposed on the firstsection. 9) The apparatus of claim 1 further comprising a connectiondisposed on the exterior surface of the separator, wherein theconnection is disposed coaxially along the longitudinal centerline ofthe first section. 10) The apparatus of claim 1 further comprising aconnection disposed on the exterior surface of the separator, whereinthe connection is disposed coaxially along the longitudinal centerlineof the second section. 11) A method for stripping particulates from aparticulate-fluid suspension comprising: introducing the particulatefluid-suspension to a vessel comprising two or more internal sectionsdisposed coaxially along a common longitudinal centerline, wherein afirst section has a first cross sectional area, and a second section hasa second cross sectional area; selectively separating the particulatefluid-suspension to provide an essentially particulate-free fluidfraction flowing in a first direction, and an essentially fluid-freeparticulate fraction flowing in a second direction within the firstsection; settling the essentially fluid-free particulate fraction intothe second section to provide one or more settled particulates therein;supplying one or more stripping fluids from an external fluid supply;introducing the one or more stripping fluids to a distribution channel;flowing the one or more stripping fluids, via a plurality of fluidconduits, from the distribution channel to a plurality of aperturesdisposed on the second section of the separator; and flowing the one ormore stripping fluids through the second section to form therein afluidized bed comprising the one or more stripping fluids and the one ormore settled particulates. 12) The method of claim 11, wherein the firstand second sections are maintained at an internal pressure equal to orgreater than ambient, external, pressure. 13) The method of claim 11,wherein the first cross sectional area is equal to the second crosssectional area. 14) The method of claim 11, wherein the first crosssectional area is greater than the second cross sectional area. 15) Themethod of claim 11, wherein at least a portion of the one or moresettled particulates are withdrawn from the second section. 16) Themethod of claim 15, wherein the level of the fluidized bed in the secondsection is maintained by controlling the withdrawal rate of the one ormore settled particulates from the second section. 17) The method ofclaim 11, wherein the separator is located within a fluid catalyticcracker (FCC) vessel and the particulate-fluid suspension comprises oneor more cracking catalysts suspended in a gas comprising one or morecracked hydrocarbons. 18) The method of claim 11, wherein the strippingfluid comprises steam. 19) A method for retrofitting a vessel toseparate particulate-fluid suspensions, the vessel providing a housingfor a first section with a first cross sectional area, the methodcomprising: installing a second section within the vessel, the secondsection having a second cross sectional area and containing one or moreapertures penetrating a wall thereof, between the first section and aparticulate discharge connection; installing one or more fluiddistribution nozzles in each of the apertures; installing a vortexstabilizer disposed coaxially along a longitudinal centerline of theseparator between the first and second sections; installing an externalfluid distribution channel, having one or more apertures disposedthereon, about the exterior of the second section; and installing one ormore fluid conduits connecting the one or more apertures disposed aboutthe fluid distribution channel to the one or more nozzles disposed ineach of the apertures penetrating the wall of the second section. 20)The method of claim 19, wherein the first cross sectional area isgreater than the second cross sectional area.